An ink jet printer is of a type injecting ink droplets through the use of an ink jet head having a plurality of nozzles to discharge the ink droplets toward a recording medium such as printing paper for directly adhering them thereonto. For example, the printing to the printing paper is made in a manner that, in a state where the ink jet head is reciprocated in cross directions of the printing paper, the printing paper is conveyed in a direction perpendicular to the moving directions of the ink jet head.
FIG. 34 is an exploded perspective view showing an essential construction of a conventional ink jet head. As FIG. 34 shows, the conventional ink jet head is equipped with a head plate 310 having a plurality of (ten in FIG. 34) of ink discharging sections 312 made therein and is made to be connected to an ink tank 320.
The ink tank 320 holds ink internally and supplies the ink through an ink supply port 322 to the head plate 310.
Each of the ink discharging sections 312 made in the head plate 310 is equipped with a nozzle for discharging ink, and is provided with an ink pressure chamber to be filled up with ink for each nozzle and an ink pressurizer for pressurizing the ink within the pressure chamber, with ink droplets being discharged from each of the nozzle when each of the ink pressurizers pressurizes the ink pressure chamber.
Incidentally, for example, as this ink pressurizer, a bimorph laminated member is known which, is composed of a piezoelectric element such as piezo and a diaphragm.
In addition, a common ink passage, not shown, is formed in the interior of the head plate 310, and the ink discharging sections 312 communicate through ink supply passages (not shown) with this common ink passage in a branched configuration.
Still additionally, an ink supply port 313 is made in the head plate 310 and communicates with the common ink passage.
Yet additionally, the head plate 310 and the ink tank 320 are coupled to each other in a manner that an adhering portion 311 of the head plate 310 and an adhering portion 321 of the ink tank 320 are adhered to each other through an adhesive or the like, and at this time, an ink outlet 322 of the ink tank 320 and the ink supply port 313 of the head plate 310 communicate with each other.
With this construction, the ink held in the ink tank 320 is supplied through the ink outlet 322 and the ink supply port 313 to the common ink passage and further delivered from the common ink passage through each of the ink communicating passages to the pressure chamber of each of the ink discharging sections 312.
In each of the ink discharging sections 312, the ink is injected from the nozzle with the pressure chamber being pressurized by the ink pressurizer, thus accomplishing the printing to printing paper.
However, in such a conventional ink jet head, an adhesive or the like is applied to the adhering portion 311 of the head plate 310 and the adhering portion 321 of the ink tank 320 and they are joined to each other for the adhesion between the head plate 310 and the ink tank 320, and hence, there is a possibility that, at this adhesion, the adhesive is forced out from adhering portions 311 and 321 to interfere with the electrodes of the ink discharging section 312 to affect the operations thereof adversely.
Therefore, in manufacturing the ink jet head, there is a need to secure a sufficient distance (adhesion allowance) between the adhering portion 311 and the ink discharging section 312 on the head plate 310, which hinders the enhancement of integration of the head plate 310, thereby making it difficult to achieve the size reduction of the head plate 310, that is, the ink jet head (in its turn, the ink jet printer)
Moreover, the head plate 310 generally has a low rigidity, in particular, in a case in which the head plate 310 is composed of a laminated substrate using a thin-film piezo as a piezoelectric element, its thickness is as low as approximately 0.2 mm, and for this reason, a problem arises in that the head plate 310 is breakable, particularly, in the process of the adhesion of the ink tank 320 to the head plate 310 or other processes, so the handling thereof requires the great care.
The present invention has been developed in consideration of these problems, and it is therefore an object of the present invention to improve the degree of integration of the head main body through the use of a worked-out construction for achieving the size reduction of an ink jet head and the size reduction of a printer as well, and further to secure a sufficient rigidity of the head main body.